The question asks the following: "If K is a positive integer less than 10 and N = 4,321 + K, what is the value of K?"

(1) N is divisible by 3.
(2) N is divisible by 7.

The correct answer is "B", because the solution explains that statement two implies only one possibility of K that will make N divisible by 7. I don't understand this implication . In other words, how can you deduce that 432 - 2(1 + K) will lead to one possibility of K?

Let's go about this one a slightly different way.

We know that N = 4,321 + K where K is a positive integer less than 10.
This means that is something between 4322 and 4330.
We know, from statement 2, that N is a multiple of 7.
There's only 1 multiple of 7 between 4322 and 4330, (it's 4326) so we know that K must be 5. This is sufficient.

Hope this helps,

Veritas Help